The vocal quintet put their signature spin on the iconic Star Wars score, with the help of composer John Williams' full symphony orchestra behind them, building even more buzz for the franchise's next installment, opening Dec. 17

Harrison Ford introduced the group's performance by giving a refresher on Williams' remarkable body of work. "Many of you know composer John Williams' name, but one thing is for sure, all movie fans know of his music," Ford said before playing some of William's most famous film scores from Jaws, E.T. the Extra-Terrestrial and Raiders of the Lost Ark.

Pentatonix began their performance completely a cappella, before Williams' orchestra chimed in for the piece for a crescendo that brought the crowd to their feet.

On the heels of their chart-topping, self-titled album, Pentatonix recently released a deluxe version of their platinum-selling holiday album, That's Christmas To Me. ET caught up with the group just last month to chat about their new, wholly original tunes and touring with Kelly Clarkson.

"This is what we do," said Kevin Olusola. "We're five people that love to sing, so it's just kind of a celebration of everything we love to do."